Lift system mountable in a nacelle of a wind turbine

ABSTRACT

A lift system mountable in a nacelle of a wind turbine has a mounting interface removably securable to a generator in the nacelle of the wind turbine, and a knuckle boom rotatably and removably mounted on the mounting interface. The knuckle boom has an extendable boom arm having a translatable boom section slidably mounted on the boom arm. Modularity of the lift system permits lifting components of the lift system up to the nacelle using an existing service crane of the wind turbine, and rapidly dismounting the knuckle boom to permit closing doors of the nacelle in the event of inclement weather without dismounting all of the lift system components.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/642,169 filed Feb. 26, 2020, which was a national entry ofInternational Application PCT/CA2018/051449 filed Nov. 15, 2018 claimingpriority to Canadian patent application 3,012,945 filed Jul. 31, 2018and claiming the benefit of U.S. Provisional Patent Application Ser. No.62/589,778 filed Nov. 22, 2017.

FIELD

This application relates to lift systems, especially to a liftingappliance mountable on wind turbines.

BACKGROUND

Wind turbines require periodic maintenance to remain operable. Due tothe extreme height at which many wind turbines operate, maintainingand/or replacing turbine parts (e.g. a rotor, blade, main bearing, mainshaft, intermediate shaft, gearbox, etc.) becomes problematic. Forreasons of safety and practicality, turbine parts are generally loweredto ground level for maintenance and/or replacement. Typically, a craneis used to lower (and then re-raise) the parts to be maintained orreplaced.

When replacing a damaged intermediate shaft (“IMS”) from a wind turbinegearbox, current state-of-the-art procedure for removing the gearboxinvolves using a large conventional crane on the ground, which is amachine having a capacity of 300 tons and a boom length of 100 meters ormore. The crane is used to remove the upper housing of the gearbox(weighing approximately 4 tons), after which the IMS is removed andreplaced with the crane. This is a tricky procedure and potentiallydangerous in high wind speeds.

There have been a number of cranes developed in the prior artspecifically adapted for maintenance of gearboxes. However, prior artcranes generally suffer from a lack of sufficient lifting capacity,which prevents them from having the ability to remove the upper housingof the gearbox. Accordingly, the upper housing must be lifted using aseparate gantry device which lifts the upper housing to allow the IMS tobe subsequently lifted with a crane.

There remains a need for a turbine-mounted crane that is capable oflifting, moving and lowering an upper housing of a gearbox and/orgearbox components of a wind turbine, particularly the turbine IMSshaft, and which preferably can be rapidly dismounted to permit closinga nacelle atop a tower of the wind turbine.

SUMMARY

In one aspect, there is provided a lift system mountable in a nacelle ofa wind turbine, the lift system comprising: a mounting interfaceremovably securable to a generator in the nacelle of the wind turbine;and, a knuckle boom rotatably and removably mounted on the mountinginterface, the knuckle boom comprising an extendable boom arm, theextendable boom arm comprising a translatable boom section slidablymounted on the boom arm.

In another aspect, there is provided a lift system mountable in anacelle of a wind turbine, the lift system comprising: a mountinginterface removably securable to a generator in the nacelle of the windturbine, the mounting interface comprising a first plurality of throughapertures; a swivel removably mounted on the mounting interface, theswivel comprising a second plurality of through apertures eachconcentrically aligned with one through aperture of the first pluralityof through apertures when the swivel is mounted on the mountinginterface, the swivel secured to the mounting interface by a pluralityof non-threaded pins removably inserted through the concentricallyaligned through apertures of the first and second plurality of throughapertures, the removable non-threaded pin permitting mounting of theswivel on and dismounting of the swivel from the mounting interface; aknuckle boom rotatably mounted on the swivel, the knuckle boom rotatableon the swivel about a vertical axis, the knuckle boom comprising anextendable boom arm, the extendable boom arm comprising a translatableboom section slidably mounted on the boom arm; a power pack mounted onthe mounting interface, the power pack comprising an electric motor anda hydraulic pump, the power pack not extending beyond a maximum heightto permit closing the nacelle when the mounting interface is mounted onthe generator and the knuckle boom is dismounted from the mountinginterface; and, a hydraulic motor for operating the swivel, thehydraulic motor connectable to the hydraulic pump by hydraulic lines andquick connect hydraulic fittings.

In another aspect, there is provided a method of mounting a lift systemin a nacelle on top of a standing wind turbine, the method comprising:lifting a mounting interface of the lift system with a power pack and aswivel mounted thereon up to the nacelle using an existing service cranepermanently mounted in the nacelle of the wind turbine, the swivelhaving a hydraulic motor mounted thereon for operating the swivel, thepower pack comprising a hydraulic pump for powering the hydraulic motorand an electric motor for powering the hydraulic pump, the mountinginterface comprising a hydraulic fluid reservoir for providing hydraulicfluid to the hydraulic pump; mounting the mounting interface on agenerator in the nacelle; lifting a knuckle boom using the servicecrane, and mounting the knuckle boom on the swivel; lifting a chain bagof the knuckle boom using the service crane, and mounting the chain bagto the knuckle boom; lifting a support bracket of the lift system with acontrol unit thereon using the service crane, and mounting the supportbracket on the mounting interface; and, connecting the control unit tothe electric motor in the power pack.

In an embodiment, the lift system may further comprise a swivelremovably mounted on the mounting interface. The knuckle boom may berigidly mounted on the swivel. The swivel may be rotatable to rotate theknuckle boom mounted thereon about a vertical axis. The swivel maycomprise a rotatable portion on which the knuckle boom is mounted. Theswivel may comprise a fixed portion comprising a first through aperture.The mounting interface may comprise a second through apertureconcentrically aligned with the first through aperture when the swivelis mounted on the mounting interface. The swivel may be secured to themounting interface by a non-threaded pin removably inserted through thefirst and second through apertures. The removable non-threaded pinpermits mounting of the swivel on and dismounting of the swivel from themounting interface. The first through aperture, the second throughaperture and the removable non-threaded pin may comprise a plurality of(for example four) first through apertures, second through apertures andremovable non-threaded pins.

The mounting interface may further comprise a third through aperturethrough which a support pin may be inserted. The swivel may comprise asupport surface having an indent in which the support pin is engaged sothat the swivel rests on the support pin when the swivel is mounted onthe mounting interface. The third through aperture and the support pinmay comprise a plurality of (for example four) third through aperturesand support pins.

The mounting interface may comprise clamps that engage protrudingelements of the generator to securely and removably mount the mountinginterface on a top of the generator. The clamps may comprise hookingportions that engage the protruding elements. The clamps may comprisebolts for tightening the clamps on the generator.

In an embodiment, the lift system may further comprise a hydraulic motorfor operating the swivel. The hydraulic motor may be mounted on theswivel or on the mounting interface, preferably on the swivel.

In an embodiment, the lift system may further comprise a power packmounted on the mounting interface. The power pack may comprise ahydraulic pump and an electric motor to power the hydraulic pump. Thehydraulic pump may be fluidly connected to the hydraulic motor to powerthe hydraulic motor. The hydraulic pump may be connectable to thehydraulic motor through hydraulic lines and hydraulic fittings. Thehydraulic fittings are preferably quick connect hydraulic fittings. Thehydraulic pump may be fluidly connected to a hydraulic manifold, thehydraulic manifold fluidly connected to the hydraulic motor and tohydraulically operated components (e.g. hydraulic cylinders) of theknuckle boom. The hydraulic pump may be fluidly connected to one or morehydraulic fluid reservoirs to receive hydraulic fluid for powering thehydraulic motor and the hydraulically operated components of the knuckleboom. The mounting interface may comprise the one or more hydraulicfluid reservoirs. The one or more hydraulic fluid reservoirs may be oneor more hollow side rails of the mounting interface in fluidcommunication with the hydraulic pump mounted on the mounting interface.The power pack mounted on the mounting interface preferably does notextend beyond a maximum height so that the nacelle may be closed whenthe mounting interface remains mounted on the generator and the knuckleboom is dismounted from the mounting interface. Doors of the nacelle maybe completely closed when the knuckle boom is dismounted and themounting interface remains mounted on the generator.

In an embodiment, the lift system may further comprise a support bracketremovably mounted on the mounting interface, the support bracket adaptedto securely support a control unit thereon. The support bracket and themounting interface may comprise mated through apertures that receiveremovable mounting pins to mount the support bracket on the mountinginterface.

The lift system is modular. The modularity of the lift system permitslifting components of the lift system up to the nacelle using theexisting service crane of the wind turbine, and rapidly dismounting theknuckle boom to permit closing doors of the nacelle in the event ofinclement weather without dismounting all of the lift system componentsfrom the nacelle. The lift system is capable of lifting heavier loadsthan the existing service cranes in the nacelles of commercial windturbines. For example, the lift system is capable of lifting an upperhousing of a gearbox of a commercial wind turbine.

Further features will be described or will become apparent in the courseof the following detailed description. It should be understood that eachfeature described herein may be utilized in any combination with any oneor more of the other described features, and that each feature does notnecessarily rely on the presence of another feature except where evidentto one of skill in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

For clearer understanding, preferred embodiments will now be describedin detail by way of example, with reference to the accompanyingdrawings, in which:

FIG. 1 depicts a rear perspective view of a lift system mounted on agenerator of a wind turbine;

FIG. 2 depicts a front perspective view of the lift system of FIG. 1mounted on the generator showing a knuckle boom of the lift systemswiveled into a different position;

FIG. 3 depicts a rear perspective view of the lift system of FIG. 1without showing the generator;

FIG. 4 depicts another perspective view of the lift system of FIG. 3showing a knuckle boom of the lift system swiveled into a differentposition;

FIG. 5 depicts a rear perspective view of a mounting interface of thelift system of FIG. 1;

FIG. 6 depicts a front perspective view of the mounting interface ofFIG. 5;

FIG. 7 depicts a top view of the mounting interface of FIG. 5;

FIG. 8 depicts a side view of the mounting interface of FIG. 5;

FIG. 9 depicts an exploded front perspective view of the mountinginterface of FIG. 5;

FIG. 10 depicts a rear perspective view of the exploded view of FIG. 9;

FIG. 11 depicts a magnified top front perspective view showing a swivelmounted on the mounting interface of FIG. 5;

FIG. 12 depicts a bottom front perspective view FIG. 10;

FIG. 13 depicts a magnified outside view of a pin arrangement formounting the swivel on the interface;

FIG. 14 depicts a magnified inside view of a pin arrangement formounting the swivel on the interface;

FIG. 15 depicts a front perspective view of the mounting interface ofthe lift system of FIG. 1 mounted on the generator, the generatormounted inside an open nacelle of the wind turbine;

FIG. 16 depicts a front perspective view of the inside of the nacelleshown in FIG. 15 with the nacelle closed;

FIG. 17 depicts a rear perspective view of the lift system mounted onthe generator in the open nacelle of the wind turbine;

FIG. 18 depicts a front perspective view of the lift system of FIG. 17showing the knuckle boom swiveled into a different position;

FIG. 19 depicts a magnified view of the mounting interface with theknuckle boom mounted thereon;

FIG. 20 depicts the lift system of FIG. 17 with the knuckle boomdeployed in a fully retracted configuration;

FIG. 21 depicts the lift system of FIG. 20 with the knuckle boompartially extended;

FIG. 22 depicts the lift system of FIG. 20 with the knuckle boom fullyextended;

FIG. 23 depicts the lift system of FIG. 17 lifting an intermediate speed(IMS) shaft inside the nacelle of the wind turbine;

FIG. 24 depicts the lift system of FIG. 23 deploying the IMS shaftoutside the nacelle for lowering the shaft to the ground; and,

FIG. 25 depicts the IMS shaft being lowered to the ground by the liftsystem.

DETAILED DESCRIPTION

With reference to the Figures, a lift system 1 is particularly usefulfor lifting and lowering a gearbox 110 or components of the gearbox 110(e.g. an intermediate speed (IMS) shaft 112) in a nacelle 100 of astanding wind turbine. Although the lift system 1 is particularly usefulfor lifting and lowering components of a gearbox, the lift system 1 mayalso be used to lift and lower other components of the wind turbine. Thelift system 1 is configured to be mounted on top of a generator 114 inthe nacelle 100.

The lift system 1 comprises a knuckle boom 5 rigidly mounted on a swivel4. The knuckle boom 5 comprises an articulated boom arm 9, having threesections 9 a, 9 b, 9 c, pivotally attached to a pedestal 6, the pedestal6 having a base plate 7 rigidly mounted to the swivel 4. The swivel 4 ismounted on a mounting interface 2, the mounting interface 2 mounted on atop of the generator 114. A chain hoist 15 is disposed proximate adistal end of the knuckle boom 5, the hoist 15 operable to raise andlower an object (e.g. the intermediate speed (IMS) shaft 112) connectedto a hook 16 of the hoist 15 with a fixed sling. The chain hoist 15hanging from the distal end of the knuckle boom 5 contains a cable orchain, which winds and unwinds when the objected is lifted and lowered.A chain bag 18 hanging beside the hoist 15 contains a sufficient lengthof chain to permit the hoist 15 to lower objects to the ground from thetop of the wind turbine. The lift system 1 further comprises a hydraulicmotor 13 mounted on the swivel 4 and a power pack mounted on themounting interface 2. The power pack comprises an electric motor 14 anda hydraulic pump 12, the electric motor 14 operating the hydraulic pump12 (see FIG. 20). The hydraulic pump 12 pumps hydraulic fluid to powerthe hydraulic motor 13, and to power hydraulic components (e.g.hydraulic cylinders) of the knuckle boom 5 as well as to power the hoist15. The hoist 15 may be powered directly by the electric motor 14, ifdesired. The electric motor 14 may receive power from the generator 114through electrical connections to the power pack. If desired, thelifting system 1 may further comprise a support bracket 10 mounted onthe mounting interface 2 and configured to rigidly but removably supporta control unit 11 thereon. The control unit 11 may include atransformer, and can be used to adapt mains power of the generator 114to an operating voltage of the electric motor 14. The electric motor 14may be situated under the support bracket 10, and the power packincluding the electric motor 14 and the hydraulic pump 12 do not extendsignificantly above the height of the mounting interface 2.

The mounting interface 2 serves as an interface between the generator114 and the other components of the lift system 1 in order to supportthe lift system 1 on the generator 114. The mounting interface 2comprises a pair of spaced-apart substantially parallel side rails 21,individually identified as a first side rail 21 a and a second side rail21 b, connected by a pair of spaced apart end brackets 22, individuallyidentified as a front-end bracket 22 a and a rear-end bracket 22 b,located at or proximate front and rear ends of the side rails 21. Theside rails 21 may be connected to the end brackets 22 by virtue of beingintegrally formed from the same piece of material (e.g. steel), bywelding the side rails 20 to the end brackets 22, or by usingconnectors, for example bolts. The side rails 21 together with the endbrackets 22 form a quadrilateral, for example a rectangle. The frontends of the side rails 21 are closer to a rotor of the wind turbine thanthe rear ends of the side rails 21 when the mounting interface 2 ismounted on the generator 114.

The side rails 21 are hollow, having interior cavities 23 (see FIG. 9and FIG. 10) in which hydraulic fluid may be stored to provide ahydraulic fluid reservoir for operating the hydraulic components of thelift system 1. The ends of the side rails 21 may be permanently closed,or may have openings, which are covered and sealed by cover plates 25(see FIG. 9 and FIG. 10, only one labeled) secured to the ends by bolts24 (see FIG. 9 and FIG. 10, only one labeled). The open ends of the siderails 21 permit filling, emptying and cleaning of the interior cavities23. Access holes 26 through the side rails 21 permit hydraulic hoses topass from under the knuckle boom 5 to a hydraulic manifold. Hydraulicfluid ports (not shown) on inner sides of the side rails 21 permit theinstallation of hose fittings to fluidly connect the hydraulic fluidreservoirs to the hydraulic pump 12 (see FIG. 20).

With specific reference to FIG. 5 and FIG. 10, the end brackets 22 ofthe mounting interface 2 comprise middle sections transversely extendingbetween and connected to the side rails 20, and pairs of feet 27generally vertically oriented and perpendicular to both the middlesection and the side rails 20. One or more of the feet 27 comprisehooking portions 28 that protrude from the feet 27 proximate bottoms ofthe feet 27, and bolting assemblies 29. The hooking portions 28 engageappropriate structures on the generator 114, while the boltingassemblies 29 engage protruding portions of the generator 114 to securethe mounting interface 2 on the generator 114 with the hooking portions28 tightly engaging the appropriate structures on the generator 114 whenbolts of the bolting assemblies 29 are tightened. Together, the hookingportions 28 and the bolting assemblies 29 act as clamps to clamp themounting interface 2 on the generator 114.

The mounting interface 2 further comprises two sets of swivel mountingflanges 41 extending inwardly between the side rails 20, the swivelmounting flanges 41 providing structure to which the swivel 4 ismounted, as described further below. The mounting interface 2 furthercomprises two sets of support bracket mounting flanges 51 protrudingoutwardly from sides of the side rails 20, the support bracket mountingflanges 51 providing structure to which the support bracket 10 ismounted, as described further below.

With specific reference to FIG. 1 and FIG. 8, when the side rails 20 ofthe mounting interface 2 are substantially parallel to the ground, topsurfaces of the swivel 4 and the support bracket 10 are angled withrespect to the ground. However, when mounted on the top of the generator114, the mounting interface 2 is angled rearwardly downward, whichresults in the top surfaces of the swivel 4 and the support bracket 10being substantially parallel to the ground.

With specific reference to FIG. 9 to FIG. 14, the swivel 4 comprises arotating portion 33 having an upper surface on which the base plate 7 ofthe pedestal 6 is bolted. The rotating portion 33 is operativelyconnected to the hydraulic motor 13, which provides power for rotatingthe rotating portion 33, and therefore the knuckle boom 5, through 360°about a vertical axis in a plane parallel to the ground. The swivelfurther comprises a fixed swivel body 31 in which the rotating portion33 rotates. The swivel body 31 comprises a pair of spaced-apart arcuatemounting arms 32. Ends of the mounting arms 32 have through apertures 35for receiving removable non-threaded mounting pins 36 therethrough. Whenthe swivel 4 is in a mounted position on the mounting interface 2, eachmounting arm 32 is engaged between the swivel mounting flanges 41 of oneof the sets of the swivel mounting flanges 41. Each set of the swivelmounting flanges 41 comprises two spaced apart swivel mounting flanges41, each swivel mounting flange 41 in a set comprising first throughapertures 45 at both ends of the swivel mounting flange 41, which alignwith similar first through apertures 45 at the ends of the other swivelmounting flange 41 in the set. The two sets of swivel mounting flanges41 are spaced apart at a distance such that one mounting arm 32 of theswivel 4 may slide between the swivel mounting flanges 41 of one set,while the other mounting arm 32 of the swivel 4 may slide between theswivel mounting flanges 41 of the other set. When the swivel 4 is in themounted position, the through apertures 35 in the mounting arms 32 alignwith the first through apertures 45 in the swivel mounting flanges 41,and the mounting pins 36 may be inserted through the aligned aperturesto secure the swivel 4 on the mounting interface 2.

Further support and security for the swivel 4 on the mounting interface2 are provided by support pins 37 on which the mounting arms 32 restwhen the swivel 4 is in the mounted position (see FIG. 12, FIG. 13 andFIG. 14). Proximate the ends and on bottom edges of the mounting arms32, the mounting arms 32 comprise indents 38 shaped and positioned sothat the mounting arms 32 rest on the support pins 37. The support pins37 are inserted through second through apertures 42 at the ends of theswivel mounting flanges 41 and secured in place with cotter pins 43.Aperture-containing brace plates 44 at the ends of each swivel mountingflange 41 may help provide structural support around the first andsecond through apertures in the swivel mounting flanges 41. The supportpins 37 firmly lock the swivel 4 to the interface 2 when the swivel 4 isoperated to rotate the knuckle boom 5.

The removable pin arrangement for mounting the swivel 4 on the mountinginterface 2 permits rapid mounting and dismounting of the knuckle boom 5from the mounting interface 2. To rapidly dismount the knuckle boom 5,hydraulic lines 17 (see FIG. 19) between the hydraulic pump 12 and thehydraulic motor 13 may be disconnected from quick connect hydraulicfittings on the hydraulic motor 13, and the four removable mounting pins36 may be removed. The knuckle boom 5 together with the swivel 4 maythen be lifted off the mounting interface 2 and lowered to the ground byan existing service crane mounted in the nacelle 100. The existingservice crane is generally a crane rated as being able to lift a maximumof 1000 kg when equipped with a heavier chain hoist. The existingservice cranes that are typically provided with wind turbines fold downinto a compact space within the nacelle 100 so that the nacelle 100 canbe normally closed. However, the existing service cranes areinsufficient for lifting heavier components of the wind turbine (e.g.gearbox components which weigh about 4 tons), hence the need for thelift system 1. The existing service crane is normally mounted in thenacelle 100 at a different location than the mounting interface 2, sothat both the existing service crane and the lift system 1 can co-existin the nacelle 100. Clamshell doors 101 of the nacelle 100 may be closedwhile the mounting interface 2 (with the power pack) remains mounted onthe generator 114 (see FIG. 15 and FIG. 16). The dismounting operationmay take as little as about 30-60 minutes. Remounting the knuckle boom 5together with the swivel 4 may be quickly accomplished by reversing thesteps.

While the removable pin arrangement is desirable for rapiddismounting/remounting of the knuckle boom 5, the knuckle boom 5 couldbe dismounted from the swivel 4 by removing all of the bolts attachingthe base plate 7 to the swivel 4. The knuckle boom 5 is then be loweredto the ground, but the swivel 4 may be dismounted from the mountinginterface 2 and moved to a different location inside the nacelle 100 inorder to close the clamshell doors 101. However, removing and replacingall of the bolts attaching the base plate 7 to the swivel 4 requiresmuch more time, and is therefore less desirable in an emergencysituation. Further, while not desirable, the swivel 4 could be mountedto the mounting interface 2 by threaded bolts or other connectors thatrequire considerably more time to remove and replace than the removablepin arrangement described above.

With specific reference to FIG. 5 to FIG. 10, the support bracket 10comprises a top plate 53 attached to a pair of spaced-apart arcuatemounting legs 52. Ends of the mounting legs 52 have through apertures 55for receiving removable non-threaded mounting pins 56 therethrough. Whenthe support bracket 10 is in a mounted position on the mountinginterface 2, each mounting leg 52 is engaged between the support bracketmounting flanges 51 of one of the sets of the support bracket mountingflanges 51. Each set of the support bracket mounting flanges 51comprises two spaced apart support bracket mounting flanges 51, eachsupport bracket mounting flange 51 in a set comprising through apertures57, which align with similar through apertures 57 of the other supportbracket mounting flange 51 in the set. The two sets of support bracketmounting flanges 51 are spaced apart at a distance such that onemounting leg 52 of the support bracket 10 may slide between the supportbracket mounting flanges 51 of one set, while the other mounting leg 52of the support bracket 10 may slide between the support bracket mountingflanges 51 of the other set. When the support bracket 10 is in themounted position, the through apertures 55 in the mounting legs 52 alignwith the through apertures 57 in the support bracket mounting flanges51, and the mounting pins 56 may be inserted through the alignedapertures to secure the support bracket 10 on the mounting interface 2.The top plate 53 of the support bracket 10 provides a horizontal surfaceon which the control unit 11 may be securely mounted (see FIG. 17 andFIG. 18).

The removable pin arrangement for mounting the support bracket 10 on themounting interface 2 permits rapid mounting and dismounting of thesupport bracket 10 with the control unit 11 thereon. To rapidly dismountthe support bracket 10, quick connect electrical fittings for electricallines (not shown) between the power pack and the control unit 11 may bedisconnected, and the four removable mounting pins 56 may be removed.The support bracket 10 together with the control unit 11 may then belifted off the mounting interface 2 and lowered to the ground by anexisting service crane mounted in the nacelle 100. The clamshell doors101 of the nacelle 100 may be closed while the mounting interface 2(with the power pack) remains mounted on the generator 114 (see FIG. 15and FIG. 16). The dismounting operation may take as little as about30-60 minutes. Remounting the support bracket 10 with the control unit11 thereon may be quickly accomplished by reversing the steps.

With specific reference to FIG. 18 to FIG. 20, the power pack (includingthe hydraulic pump 12 and the electric motor 14) is mounted on themounting interface 2 proximate the swivel 4 and the support bracket 10in order to locate the power pack close to the hydraulic components onthe swivel 4 and the knuckle boom 5, and close to the control unit 11 toreduce the length of the hydraulic lines 17 and electrical lines (notshown) required to connect the power pack to the various hydraulic andelectrical components of the lift system 1. The hydraulic motor 13 ismounted on the swivel 4, and accompanies the swivel 4 when the swivel 4is dismounted from the mounting interface 2. The power pack ispositioned so that the power pack, including the hydraulic pump 12 andthe electric motor 14, does not extend significantly above the height ofthe mounting interface 2, thereby ensuring sufficient clearance abovethe mounting interface 2 to be able to close the clamshell doors 101 ofthe nacelle 100 without needing to dismount the mounting interface 2from the generator 114 (see FIG. 16).

Quick connect power fittings (hydraulic and electrical) and the pinarrangements for mounting the swivel 4 and the support bracket 10 on themounting interface 2 provide modularity to the lift system 1, whichadvantageously permits rapidly dismounting various components of thelift system 1 and closing the nacelle 100 in emergency situations, forexample in inclement weather, while the mounting interface 2, with thepower pack, remains mounted on the generator 114. When the emergency isover, the nacelle 100 can be re-opened and the various components can berapidly remounted.

With specific reference to FIG. 20 to FIG. 25, the knuckle boom 5comprises the base plate 7, the pedestal 6 and the articulated boom arm9. The knuckle boom 5 is attached to the swivel 4 by base plate 7, andthe pedestal 6 is vertically oriented and rigidly attached to the baseplate 7. The articulated boom arm 9 comprises a first boom section 9 apivotally mounted to the pedestal 6 at or proximate a proximal end ofthe first boom section 9 a. The articulated boom arm 9 further comprisesa second boom section 9 b pivotally mounted to the first boom section 9a at or proximate a distal end of the first boom section 9 a and at orproximate a proximal end of the second boom section 9 b. The articulatedboom arm 9 further comprises a third boom section 9 c translatablymounted alongside the second boom section 9 b.

The swivel 4 permits rotation of the knuckle boom 5 around a full 360°circle in a horizontal plane so that the knuckle boom 5 can operatewithin and outside the nacelle 100, and can operate on all sides of thenacelle 100. Actuators 8, individually labeled as 8 a, 8 b and 8 c,control pivoting and translation of the articulated boom 9. Theactuators 8 a, 8 b, 8 c may be any suitable actuators or combination ofactuators, for example hydraulic cylinders, linear actuators, pneumaticcylinders, screw actuators, etc. The actuator 8 a controls pivoting ofthe first boom section 9 a in a vertical plane. The actuator 8 bcontrols pivoting of the second boom section 9 b in a vertical plane.The actuator 8 c controls translation of the third boom section 9 c in adirection in which the second boom section 9 b is pointing. Thus,operation of the actuator 8 c effectively increases and decreases thereach of the knuckle boom 5 by extending and retracting the third boomsection 9 c, which slides alongside the second boom section 9 b relativeto the second boom section 9 b. While the second boom section 9 b ispivotable on the first boom section 9 a, which affects the reach of thesecond boom section 9 b, the second boom section 9 b does not slide.Using the translatable third boom section 9 c to further increase anddecrease the reach of the knuckle boom 5 is convenient for operatorsworking on the gearbox 110, which is located some distance from thegenerator 114. The knuckle boom 5 described above provides the requiredreach, while staying within an acceptable weight limitation for theknuckle boom 5.

Each of the modular components of the lift system 1 are sized to belifted by the existing service crane on the wind turbine. Disassemblypoints and overall weight of each modular component are carefullyselected in view of a lifting procedure for raising the entire liftsystem 1 up to the nacelle 100 where the lift system 1 is assembled. Theprocedure for raising the lift system 1 up to the nacelle 100 comprises:

-   -   1. opening the clamshell doors 101 and erecting the existing        service crane;    -   2. using the existing service crane to lift an intermediate        lifting hoist, which extends the capacity of the service crane        cable from 250 kg to 1000 kg;    -   3. lifting the mounting interface 2 with the power pack and        swivel 4 thereon using the service crane and intermediate hoist,        and mounting the mounting interface 2 on the generator 114 in        the nacelle 100;    -   4. lifting the knuckle boom 5 using the service crane and        intermediate hoist, and mounting the base plate 7 to the swivel        4;    -   5. lifting the chain hoist 15 using the service crane and        intermediate hoist, and mounting the chain hoist 15 to the        knuckle boom 5;    -   6. lifting the support bracket 10 with the control unit 11        thereon using the service crane and intermediate hoist, and        mounting the support bracket 10 on the mounting interface 2;    -   7. connecting the control unit 11 to the electric motor 14 in        the power pack; and,    -   8. optionally lowering the existing service crane to its normal        location within the nacelle 100, if it is not anticipated that        it will be required for inclement weather.

The lift system 1 allows a single crane to be used to raise and lower anupper housing of the gearbox 110, to lift and lower a canopy of thenacelle 100 and to lift and lower gearbox components, due, at least inpart, to the longer reach provided by the knuckle boom 5 with thetranslating third boom section 9 c, the greater lift capacity and thesufficiently low weight that the lift system 1 can be raised up to thenacelle 100 using the limited existing service crane.

The novel features will become apparent to those of skill in the artupon examination of the description. It should be understood, however,that the scope of the claims should not be limited by the embodiments,but should be given the broadest interpretation consistent with thewording of the claims and the specification as a whole.

1. A lift system mountable in a nacelle of a wind turbine, the liftsystem comprising: a mounting interface removably securable to agenerator in the nacelle of the wind turbine; a swivel rotatably andremovably mounted on the mounting interface; a hydraulic motor foroperating the swivel; a power pack comprising a hydraulic pump and anelectric motor for operating the hydraulic pump, the hydraulic pumpconnectable to the hydraulic motor through hydraulic lines and quickconnect hydraulic fittings; and, a knuckle boom rigidly mounted on theswivel, the knuckle boom comprising an extendable boom arm, theextendable boom arm comprising a translatable boom section slidablymounted on the boom arm, wherein the swivel is rotatable to rotate theknuckle boom mounted thereon about a vertical axis, and wherein thepower pack is mounted on the mounting interface and does not extendbeyond a maximum height to permit closing the nacelle when the mountinginterface is mounted on the generator and the knuckle boom is dismountedfrom the mounting interface.
 2. The lift system of claim 1, wherein themounting interface comprises clamps that engage protruding elements ofthe generator to securely and removably mount the mounting interface ona top of the generator.
 3. The lift system of claim 1, wherein: theswivel comprises a rotatable portion on which the knuckle boom ismounted and a fixed portion comprising a first through aperture; themounting interface comprises a second through aperture concentricallyaligned with the first through aperture when the swivel is mounted onthe mounting interface; and, the swivel is secured to the mountinginterface by a non-threaded pin removably inserted through the first andsecond through apertures, the removable non-threaded pin permittingmounting of the swivel on and dismounting of the swivel from themounting interface.
 4. The lift system of claim 3, wherein the firstthrough aperture, the second through aperture and the removablenon-threaded pin comprise a plurality of first through apertures, secondthrough apertures and removable non-threaded pins.
 5. The lift system ofclaim 3, wherein the mounting interface further comprises a thirdthrough aperture through which a support pin is inserted, the swivelcomprising a support surface having an indent in which the support pinis engaged so that the swivel rests on the support pin when the swivelis mounted on the mounting interface.
 6. The lift system of claim 5,wherein the third through aperture and the support pin comprise aplurality of third through apertures and support pins.
 7. The liftsystem of claim 1, wherein the mounting interface comprises one or morehydraulic fluid reservoirs.
 8. The lift system of claim 7, wherein theone or more hydraulic fluid reservoirs is one or more hollow side railsof the mounting interface in fluid communication with a hydraulic pumpmounted on the mounting interface.
 9. The lift system of claim 2,wherein the clamps comprise hooking portions that engage the protrudingelements, and further comprise bolts for tightening the clamps on thegenerator.
 10. The lift system of claim 1, further comprising a supportbracket removably mounted on the mounting interface, the support bracketadapted to securely support a control unit thereon.
 11. The lift systemof claim 10, wherein the support bracket and the mounting interfacecomprise mated through apertures that receive removable mounting pins tomount the support bracket on the mounting interface.
 12. The lift systemof claim 1, wherein the knuckle boom is able to lift an upper housing ofa gearbox of the wind turbine.